Clean hydrogen production is essential for decarbonising energy-intensive industries. Ammonia is a promising hydrogen carrier because it can be stored and transported using existing global infrastructure. However, its conversion to high-purity H₂ must be efficient, durable, and economically viable. Electrochemical ammonia “e-cracking”, which couples ammonia oxidation reaction (AOR) at the anode with hydrogen evolution at the cathode in a membrane–electrode assembly (MEA), provides a low-temperature and modular alternative to thermal ammonia cracking. Its practical application, however, is still limited by high cell voltage, catalyst deactivation, ammonia crossover, feed utilisation losses, and stack durability issues. This thesis combines techno-economic analysis (TEA) with catalyst and materials design to guide the development of practical AOR-MEA systems. Chapter 2 establishes a TEA framework that links key device metrics, including cell voltage, current density, Faradaic efficiency, ammonia utilisation, and stack lifetime, to energy consumption and the levelized cost of hydrogen. Chapter 3 develops a pulsed-electrodeposited Pt catalyst enriched with Pt(100) sites, achieving improved poisoning resistance and long-term MEA stability. Chapter 4 further improves AOR performance through PtLaSc alloying, where La enhances activity and Sc improves structural stability. Overall, this thesis provides cost-guided design principles and catalyst strategies for decentralised hydrogen production from ammonia.